7 vs 8 pin skip vs full

[IffykidMn]

I guess I should mention that what I use a saw for is felling and topping and limbing. Not a firewood feller. Cutting oak, hickory, poplar, maple, walnut, ash, etc. (Logging) so all the stump activities (face cuts, boring, back barring, sectional cutting, etc). And I guess doing all those different cuts requires a good dose of forgiveness to really make for a good worksaw. Something that you don’t have to fight for several hours at a time.

Most comes down to trade offs, I do not care for dragging anything much over 24" around in the brush and limbs so.
70cc 24" 7 pin
90cc 24" 8 pin to keep the saw from bouncing off the rev limiter as much but still has a fair bit more oooomph than the 70cc 7 pin.
both full house full comp.
Tree avg 20-30" if tress ran bigger or smaller average I might reconsider my setup.

back 40 odd years ago cutting pulpwood it was a 70cc 7 pin with 20" b&c.

 

[pbillyi69]

i didnt do any timed tests. . on my 372xpw it came with a 7 pin on a 32" inch bar running semi skip square chain. it seemed to cut a little slower than my cousins 372oe with the same chain so i put an 8 pin on it. we think it sped it up in cut time but like i said we didnt time it. that saw has had that set up since and i have never been let down by it and it cuts fast enough. the key is and always will be a sharp chain. when it dulls change it dont just keep cutting with a dull chain because it actually damages the chain by over heating it. i have sharpened a lot of chain for other people who say that their chains dont stay sharp for very long and its because they run them when they are dull. full skip tooth chains on short bars is pointless they dont cut as well as they would with full comp. skip chain is meant for long bars buried the full length of the bar the missing cutters is to allow room for chips to be cleared without bogging the saw down.

 

[pbillyi69]

i forgot to say that if your saw has enough power to pull a full comp chain it will cut faster the down side is there a lot more sharpening to do...thats why my chain is semi skip for the long bars and full for the short bars

 

[Semotony]

Say a feller has a good running 70-80cc saw. Cutting hardwoods. Running 28” bar. In terms of cutting speed. Would he be better off running a:
1.skip chain with an 8 pin rim
2. Skip chain with a 7 pin rim
3. Full comp chain with 7 pin rim
4. Full comp chain with 8 pin rim
And when I say good running saw I mean a machined and ported saw. Running 3/8” pitch .050 gauge. Any and all input appreciated

As a guy that has run a 5 foot b&c milling (Lotta stress) stuff, my best speed of travel down a log has been 8 pin with skip chain. Skip chain allows more gap for chips, less bind in the mid area of cut and beyond. The skip has half the cutters so running faster (8 pin rim) doesn't equal the resistance of the cutters of comp chain.
Your mileage may vary

 

[Semotony]

Well lemme ask this. What about .325 chain on a saw like I mentioned in the OP. I’ve been hearing some buzz about 325 on larger saws with 28”+ bars… what’s all that about??

Run that 36" bar on a 046 stihl. Cutters look like mini full chisel and it mills faster than 3/8 .063. Less wood being cut is all I can figure. It also leaves a bit smoother surface.

 

[Woodwackr]

Why not throw a 6-pin into the mix?

13" .325 6-pin on a 40-50cc? Little torque monster firewood machine.....?

never seen a 6t rim sprocket for anything...just spur sprockets.

 

[HumBurner]

never seen a 6t rim sprocket for anything...just spur sprockets.

Little bit of searching shows you are most certainly correct on this!

That's a shame there are no 6t rims, but the market is probably so miniscule its not worth production. Ugh, I hate spurs!

 

[davidwyby]

It maybe be that 6 is too small and the chain cannot bend that tight.

 

[huskihl]

It maybe be that 6 is too small and the chain cannot bend that tight.

By the time the crank was small enough to get a bearing, drum, and 6t rim over it, I think the crank might be weak

 

[Nutball]

7t is probably the better bet for hardwood with that size of saw. I'd prefer full skip on a 28". I will say that I sometimes prefer an 8t with that much power to reduce torque on the chain, so it doesn't stretch as easily.

Ported 70-80cc will run .325 well with a 9t, which is just slightly larger than a 8t 3/8. I think .325 gets 1 extra tooth for every 14 teeth on 3/8, but I don't know if full skip is made in .325.

 

[Nutball]

Little bit of searching shows you are most certainly correct on this!

That's a shame there are no 6t rims, but the market is probably so miniscule its not worth production. Ugh, I hate spurs!

I have seen a 5t spur for 3/8lp. No room for a bearing if I remember correctly, not that it can't be done, but it was on a gear drive corded electric.